Add PostgreSQL database persistence

- Add connect_machines, connect_sessions, connect_session_events, connect_support_codes tables
- Implement db module with connection pooling (sqlx)
- Add machine persistence across server restarts
- Add audit logging for session/viewer events
- Support codes now persisted to database

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

server/src/main.rs

@@ -38,6 +38,7 @@ use support_codes::{SupportCodeManager, CreateCodeRequest, SupportCode, CodeVali
 pub struct AppState {
     sessions: session::SessionManager,
     support_codes: SupportCodeManager,
+    db: Option<db::Database>,
 }
 
 #[tokio::main]
@@ -52,15 +53,55 @@ async fn main() -> Result<()> {
 
     // Load configuration
     let config = config::Config::load()?;
-    
+
     // Use port 3002 for GuruConnect
     let listen_addr = std::env::var("LISTEN_ADDR").unwrap_or_else(|_| "0.0.0.0:3002".to_string());
     info!("Loaded configuration, listening on {}", listen_addr);
 
+    // Initialize database if configured
+    let database = if let Some(ref db_url) = config.database_url {
+        match db::Database::connect(db_url, config.database_max_connections).await {
+            Ok(db) => {
+                // Run migrations
+                if let Err(e) = db.migrate().await {
+                    tracing::error!("Failed to run migrations: {}", e);
+                    return Err(e);
+                }
+                Some(db)
+            }
+            Err(e) => {
+                tracing::warn!("Failed to connect to database: {}. Running without persistence.", e);
+                None
+            }
+        }
+    } else {
+        info!("No DATABASE_URL set, running without persistence");
+        None
+    };
+
+    // Create session manager
+    let sessions = session::SessionManager::new();
+
+    // Restore persistent machines from database
+    if let Some(ref db) = database {
+        match db::machines::get_all_machines(db.pool()).await {
+            Ok(machines) => {
+                info!("Restoring {} persistent machines from database", machines.len());
+                for machine in machines {
+                    sessions.restore_offline_machine(&machine.agent_id, &machine.hostname).await;
+                }
+            }
+            Err(e) => {
+                tracing::warn!("Failed to restore machines: {}", e);
+            }
+        }
+    }
+
     // Create application state
     let state = AppState {
-        sessions: session::SessionManager::new(),
+        sessions,
         support_codes: SupportCodeManager::new(),
+        db: database,
     };
 
     // Build router